Radio frequency heating assisted Maillard reaction of whey protein - gum Arabic: Improving structural and unlocking functional properties

Whey protein (WP) is a highly nutritious animal protein, but its functional properties are sensitive to environmental factors, such as temperature, pH, and ionic strength, which prevent its applications in various food systems. The conjugation of proteins with polysaccharides via the Maillard reaction is an efficient method to improve their functionalities. The purpose of this study was to use radio frequency (RF) heating technology to assist the covalent coupling of WP and gum Arabic (GA) for improving their grafting efficiency and functional properties. Results showed that under the optimal condition of RF heating, the degree of glycosylation (DG) of the conjugate could reach 19.19 %, while the maximum DG value of the conjugate obtained by water bath (WB) heating was only 10.60 %. There was a good correlation between the DG and dielectric properties of WP-GA conjugates. Structural analysis revealed that compared with their mixtures, the network structure of WP-GA conjugates was clear, the content of β-turn and random coil increased, and the fluorescence intensity and surface hydrophobicity decreased. In addition, glycosylation enhanced the emulsifying, foaming, and antioxidant properties of WP-GA conjugates. This study indicates that the RF heating technology has potential application values in the glycosylation modification of proteins.